Direct immobilization of glucose oxidase in magnetic mesoporous bioactive glasses

Direct immobilization of enzymes on the bioactive glasses is conceptually a completely new strategy. We find that the Fe₂O₃-CaO-SiO₂-P₂O₅ magnetic mesoporous bioactive glass (MMBG) is an ideal immobilization matrix for glucose oxidase (GOD). Its unique chemical surface properties and open mesopores enhance the catalytic activity of directly immobilized GOD. In this paper, MMBG was synthesized using the sol-gel approach and polyethylene glycol (PEG) as template at 700 °C. GOD molecules were spontaneously entrapped inside the open mesoporous structure and onto the surface of MMBG via iron ion binding, their activity was not impaired. The substrates and products can access and diffuse freely through the open mesoporous structure in MMBG. This study is focused on understanding the formation mechanism of MMBG, the immobilized mechanism of GOD and the magnetic separation mechanism of MMBG from the reaction medium. The MMBG can be utilized in the design of a solid support for any enzyme for bioconversion, bioremediation, and biosensors.